This morning I was seeing a patient, who is pregnant, for an exam (for an unrelated issue). When I asked for her due date she replied that her "estimated date of confinement," a term she'd clearly picked up from her OB, was in May of next year. I suddenly realized that the term "EDC," which is an abbreviation doctors use all the time, stands for just that - "Estimated Date of Confinement." It's one of those acronyms I got into the habit of using without thinking about its meaning.

The patient: "I thought 'estimated date of delivery' would make more sense, but that's the way they [the OB] said it."

I responded: "Medicine has archaic terms that still crop up even when you don't expect them. 'Confinement' used to be the term they used for delivering a baby. We still say 'EDC' even though it doesn't really make sense anymore."

We both laughed as I added: "It's like, 'She's pregnant. Confine her!'"